Boom mounted coiled tubing guide and method for running coiled tubing

ABSTRACT

A coiled tubing support guide for maintaining an arch in a length of coiled tubing as it is unwound from a storage reel and feed into a coiled tubing injector connected with a wellhead is mounted to an elongated support structure rather than to the coiled tubing injector. The elongated support structure bears a load created by tension placed on the coiled tubing by the reel, thereby avoiding putting a bending moment on the wellhead. In alternate embodiment, a coiled tubing injector being held by a hoist line from the elongated support structure is coupled to the elongated support structure with a bending-resistant coupling that permits relative rotation of the coiled tubing injector.

This application claims the benefit of U.S. Provisional Application No.61/583,230 filed Jan. 5, 2012, which is incorporated in its entirety,for all purposes, by reference.

TECHNICAL FIELD OF THE INVENTION

The invention pertains generally to oilfield operations involving use ofcoiled tubing.

BACKGROUND

Coiled tubing is commonly used in a wide range of oilfield services andoperations. It can be run into and out of a well bore at a high rate,relative to straight, jointed pipe, and, unlike wire line, it can bepushed into the well bore. Coiled tubing refers to a continuously stringof steel pipe that is continuously milled and coiled onto a largetake-up reel for transportation and handling. With diameters from 0.75inches to more than 4 inches, coiled tubing can possess a yield andtensile strengths from 50,000 pounds-force per square inch (PSI) to morethan 120,000 PSI, and has been manufactured in lengths greater than30,000 feet. It can be used, for example, for drilling, but it is moreoften used after the well is drilled for logging, cleanouts, fracturing,cementing, fishing, completion and production related operations.

Coiled tubing is run in and out of well bores using machines calledcoiled tubing injectors. The name “coiled tubing injector” derives fromthe fact that, in preexisting well bores, the tubing may need to beforced or “injected” into the well through a sliding seal to overcomethe pressure of fluid within the well, until the weight of the tubing inthe well exceeds the force produced by the pressure acting against thecross-sectional area of the pipe. However, once the weight of the tubingovercomes the pressure, it must be held by the injector.

There are a number of different types and configurations of coiledtubing injectors capable of handling coiled tubing used in oilfieldoperations. Most coiled tubing injectors have a head comprised of twocontinuous chains, each mounted on sets of spaced-apart sprockets, sothat there is an extended length of chain between the sprockets. Atleast one of the chains is driven by a motor—typically hydraulic, thoughother types of motors can be used—connected to one or more of thesprockets. The chains are arranged so that the coiled tubing enteringthe injector is held between the chains by grippers mounted to each ofthe chains. The grippers are pressed against the outer diameter of thetubing thereby generating a frictional force parallel to the axis of thetubing. The frictional force is directly related to the normal forceapplied by the grippers.

FIGS. 1 and 2 illustrate examples of equipment typically used whenconducting operations on a previously drilled well after a drilling righas been removed. A reel 10 of coiled tubing is mounted on a trailer 11for transport to the site. A coiled tubing injector, control cabin andother equipment for operating the injector is sometimes referred to as a“coiled tubing unit,” and is generally designated in the figures by thereference number 12. As coiled tubing 14 is unspooled from the reel, oris spooled back onto the reel, it is guided into alignment with thechains of the coiled tubing injector by a tubing support guide 16.Because such guides are typically arched, they are sometimes referred toas “gooseneck” supports. When the coiled tubing injector is deployed,the guide is connected to the frame of the coiled tubing injector sothat it has a fixed relationship with the coiled tubing injector whilethe injector is being operated. Generally, the guidance arch ispositioned or oriented so that the coiled tubing is thread into the topof the head of the injector, between its rotating chains or, optionally,into a straightener mounted to the frame, on top of the injector head,for removing the bend in the tubing before it enters the injector head.(As used in this description, “coiled tubing injector” refers to theinjector head with or without the straightener, unless the contextindicates otherwise.) The reel must maintain tension on the coiledtubing in order to wind the tubing coiled on the reel and to keep itwound on the reel, as it is being unspooled or spooled. The guidancearch prevents the coiled tubing from kinking or otherwise being damagedby the tension the reel is applying to the tubing. However, a guidancearch is typically attached to the frame of the coiled tubing injector ina manner that allows it to be attached or connected in differentpositions or orientations. For example, the best positioning ororientation may depend on the diameter of tubing being used and whetherthe tubing is being lowered or pushed into the well bore or pulled outof the well bore. When the pipe is coming off a reel, it has relativelymore curve than when it is pulled from the well, which may affect howthe guidance arch is fixed to the injector. Thus, “fixed relationship”does not imply one that cannot allow for adjustment.

When being used, the coiled tubing injector is positioned over the wellhead, high enough to accommodate one or more blow out preventers 20, ariser 22, and other equipment that might be connected to the wellheadthrough which the coiled tubing must pass before entering the well bore.The riser is made up from one or more sections of straight pipe thatextends from the blow out preventers attached to the wellhead. The riseris used to accommodate elongated, rigid tools that are attached to theend of the coiled tubing prior to being lowered into the well bore. Thecoiled tubing injector is connected to the riser with a stripper,through which the coiled tubing is pushed or pulled. Because there is noderrick or platform, a temporary structure erected above the wellhead,or a mobile crane driven to the site, is used to position and hold theinjector in place.

FIG. 1 illustrates an example of the use of a portable structure 24,which is temporarily erected from one or more stackable sectionstransported to the site, for holding the coiled tubing injector in placeabove the wellhead. FIG. 2 illustrates the use of a high capacity,self-propelled crane 26 to lift and hold the coiled tubing injector 18and guidance arch in the proper position during the well servicing job.The crane is generally placed opposite the wellhead of the coiled tubingreel 10 or, if necessary, to one side. Some or all of the weight of theinjector and the tubing is transferred to the boom of the crane.However, the tension on the section 14 of coiled tubing between coiledtubing injector 18 and the reel 10 also applies a lateral force on theguidance arch 16, which is transferred to the coiled tubing injector 18,inducing a bending moment on the wellhead. Taller wellheads, which areincreasingly used to accommodate long downhole tools and larger diametercoiled, tubing, mean greater bending moments. The structure 24 can bedesigned to handle the load expected from the bending moment. However,in the case of the crane, the crane operator has to operate the crane ina manner that places an opposing force on the coiled tubing injector 18.This opposing force is usually applied by pulling back and away from thereel 10 in an attempt to reduce the tension loads that produce thebending moment on the wellhead. Knowing how hard to pull back on thetubing injector usually involves guesswork and, in some situations, thetension in the tubing can exceed the capacity of the crane to hold alateral force. There have, therefore, been a number of instances inwhich wellheads have been pulled over and cranes toppled.

SUMMARY

As the diameter, wall thickness and yield strength of coiled tubing usedin well operations increases, more tension on the coiled tubing will berequired to wind it around a storage reel. Reels will need to imposehigher tensions on the segment of coiled tubing extending between thereel and the coiled tubing injector. Furthermore, larger tubing alsorequires taller wellheads. More tension and taller wellheads result inmuch higher bending moments applied on the wellheads.

In one example of a method and apparatus for conducting well servicingoperations using coiled tubing, a coiled tubing guide for supportingcoiled tubing as it turns into the top of a coiled tubing injector isaffixed to a support structure, above a coiled tubing injector, withoutit being affixed to the coiled tubing injector. The load induced bytension on the coiled tubing is transferred through the coiled tubingguide to the support structure rather than to the coiled tubinginjector. The tension from the reel thus no longer induces a bendingmoment in the wellhead. Greater tension can be applied to the coiledtubing by the reel without increasing bending moment on the wellhead.

In another example, a boom of a crane holding a coiled tubing injectorabove a wellhead is fitted with a tubing guide for supporting coiledtubing as it transitions from the reel into the coiled tubing injector.Alternately, a crane or extendable mast positions the coiled tubingguide above the coiled tubing injector, while the coiled tubing injectoris held by a separate crane.

In yet another example, the reel is positioned with respect to anelongated support structure such as a crane boom or telescoping mast, sothat the majority of the load induced by the tension on the coiledtubing is borne primarily as an axial, compressive load by the elongatedsupport. Although a bending load is also placed on the elongated supportstructure, to the extent that it is upward, it counters the downwardbending load on the mast caused by the coiled tubing injector if it isbeing supported by the elongated support structure, and the weight ofthe elongated support structure. By more closely aligning the inducedload with the axis of the elongated support structure, the guessworkinvolved with operating that structure, in particular a crane, tocounteract the load is lessened.

In yet another example, the coiled tubing guide is attached to the craneboom or telescoping mast using a coupling for allowing it to tilt and/orto swivel side-to-side. This adjustability allows the angle between thecoiled tubing and the elongated member carrying the coiled tubingsupport boom angle to vary, thereby allowing more flexibility inpositioning the elongated support structure and the reel.

In an alternate embodiment of a method and apparatus for conducting wellservicing operations using coiled tubing, an injector with coiled tubingguide is suspended from a crane boom, telescoping mast or otherelongated support structure and coupled with an end of the elongatedsupport structure through a coupling that resists bending whilepermitting, at least during movement of the coiled tubing injector abovethe well head, relative rotation of the coiled tubing injector withrespect to the crane. The coiled tubing guide is not mounted to the endof the crane. The coupling prevents a bending moment from being appliedto the wellhead as a result of the tension of the coiled tubing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a prior art arrangement of equipmentused for running coiled tubing in a bore of an oil or gas well.

FIG. 2 is a perspective view of a prior art arrangement of equipmentused for running coiled tubing in a bore of an oil or gas well.

FIG. 3 is a perspective view of an example of a support for guidingcoiled tubing mounted to a boom of a crane holding a coiled tubinginjector.

FIGS. 4A and 4B are side views of a coupling for connecting a coiledtubing support guide to mast or boom of a crane in two differentpositions.

FIGS. 4C and 4D are bottom views of the coupling of FIG. 4A in twodifferent positions or orientations.

FIGS. 5A and 5B are side views of an alternate coupling for connectingcoiled tubing support guide to a mast or boom.

FIGS. 6A and 6B are side and front views of another arrangement of acoiled tubing support guide connected to a boom of a crane.

FIG. 7 is a side view of an alternative coiled tubing support guideconnected to a boom of a crane.

FIGS. 8A and 8B are front and side views of yet another arrangement of acoiled tubing support guide connected with a boom of a crane.

FIG. 9 is a side view of a telescoping mast, to which a coiled tubingsupport guide is attached, holding a coiled tubing injector above wellhead, and a coiled tubing unit positioned in line with the mast and thewell head, but behind the vehicle carrying the mast.

FIG. 10 is another alternate embodiment with a coiled tubing supportguide attached to a mast working in conjunction with a crane thatsupports a coiled tubing injector.

FIG. 11 is a side view of an alternative embodiment, to the example ofFIG. 9, with a mobile, self-propelled crane in place of telescopingmast.

FIG. 12 is a side view of the components of FIG. 11, with the coiledtubing unit placed beside the crane rather than in line with the craneand wellhead.

FIG. 13 is a side view of another alternative example of an arrangementof a coiled tubing support guide on a crane, from which a coiled tubinginjector is suspended, with a coiled tubing unit positioned between awellhead and the crane.

FIG. 14 is a side view of an alternative example of an arrangement of acoiled tubing support guide on a crane, from which a coiled tubinginjector is suspended, with a coiled tubing unit positioned opposite awellhead from the crane.

FIG. 15A is a side view in representative environment of a first examplea bending-resistant coupling formed between the end of crane boom and acoiled tubing injector unit.

FIG. 15B is a perspective view of just the coupling of FIG. 15B.

FIG. 15C is a perspective view of the coupling of FIGS. 15A and 15B,without being attached to a crane.

FIG. 16A is a side view in representative environment of a secondexample a bending-resistant coupling formed between the end of craneboom and a coiled tubing injector unit.

FIG. 16B is a perspective view of just the coupling of FIG. 16B.

FIG. 16C is a perspective view of a detail of FIG. 16B, showing tworings of the coupling in an engaged and a disengaged position.

FIG. 17 is a perspective side view in a representative environment of analternate method and apparatus for countering a side force on a coiledtubing unit by a crane that uses extension arm for enabling rigging of aline to counteract a side force on the coiled tubing injector.

FIG. 18 is a top or plan view showing placement of a crane with respectto a coiled tubing unit and wellhead for hoisting and positioning the acoiled injector over the well head.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the following description, like numbers refer to like elements.

In each of the examples of FIGS. 3-17, a coiled tubing injector 18 forinjecting coiled tubing 34 into a well bore is positioned above thewellhead by an elongated support structure. An example of such anelongated support structure include crane 26 with a telescoping boom 38.Another example of such an elongated support structure is a telescopingmast 60, as shown in FIGS. 9-10.

A coiled tubing unit typically comprises a frame 18 a to which ismounted a coiled tubing injector head 18 b. However, in otherembodiments, a coiled tubing injector can include more components,including for example a straightener. In other embodiments, the unitmight omit an external frame, like frame 18 a. The coiled tubing enters,in the examples of FIGS. 3-14 and 16-17, a straightener 19 that ismounted on top of a frame 18 a of the coiled tubing injector 18. Nostraightener is shown in example embodiments of FIGS. 15A-15C, howeversuch embodiments could be adapted to accommodate one. The tubing exitsthe straightener and enters the top of the coiled tubing injector head.The coiled tubing injector head 18 b is, in this example, comprised of apair of opposed endless chains with grippers (not visible) for conveyingthe tubing in and out of the wellhead. Coiled tubing 34 is fed from reel10 into riser 22 when being lowered into the well. The elongated supportstructure (e.g. boom 38 of the crane or extendable mast 60) is used toposition the coiled tubing injector 18 above the wellhead. The coiledtubing injector hangs from a main hook 42 that is connected by a mainhost line 44 to the head 40 of the elongated support structure. Upwardand downward movement of the main hook 42 is directed by the main hoistline 44. The head 40 of the elongated support structure typicallyincludes at least one sheave 45 or other type of wheel or pulley,rotably mounted on a load shaft 47, around which the hoist line is run.

The coiled tubing 34 is spooled at one end to a storage reel (notvisible), such as reel 10 of FIGS. 1 and 2. The other end is routed fromthe storage reel upward to a coiled tubing guide, which, in thisexample, is comprised of an arched support guide 36, which is sometimesreferred to as a gooseneck. The radius of the arched support guide 36supports the coiled tubing 34 as it turns into the top of the coiledtubing injector, allowing the change of direction of the coiled tubing34, from the upward direction from the storage reel to the downwarddirection to be received in the top of the coiled tubing injector 18.The radius or curvature of the arch allows the change in directionwithout kinking or otherwise excessively damaging the coiled tubing,which is under tension by the reel. (Note that coiled tubing is designedto be plastically deformed when it is wound and unwound from the reel,or otherwise gently bent, through a number of cycles.)

According to certain embodiments, the arched support guide 36 mayfurther comprise a series of rollers to reduce the friction with thecoiled tubing as it moves along the arched support guide 36. In theembodiment shown in FIG. 3, the arched support guide 36 is disposedgenerally above and in-line with the boom 38. Alignment with the boomaxis of the boom permits the line of force caused by the tension of thecoiled tubing to be generally aligned with the axis to the boom of thecrane, resulting in a majority of the load to be carried by the boom asan axial load with any remaining load causing a bending moment.

The coiled tubing support guide is, in the embodiment illustrated inseveral of the figures, including FIG. 3, attached to the boom of thecrane by adjustable coupling 46. Alternately, the coiled tubing supportguide is attached to the boom in a manner that does not allow theposition or orientation of the tubing support guide to be adjusted, sothat it has a fixed relationship to the central axis of the boom whenattached. For example, the plane of the tubing support guide is alignedwith the central axis of the boom or at a fixed angle to the centralaxis of the boom. The coiled tubing support guide is, in certainembodiments, such as the one shown in FIG. 3, detachable or removablefrom the boom of the crane or other elongated support structure to allowfor easier transportation.

An adjustable coupling, such as coupling 46, allows the position of thearched support guide, or any other type of coiled tubing support guide,to be adjusted along multiple axes. For example, an adjustable couplingmay permit the arched support guide 36 to be adjusted by tilting itforward and backward. This allows better control over the routing of thecoiled tubing and provides adjustability of the angle of the boom 38with respect to the coiled tubing. In another embodiment, the adjustablecoupling may permit the coiled tubing support guide to be moved or swungfrom one side of the boom to the other side and/or rotated so that theplane of the coiled tubing support guide is at an angle to the axis ofthe boom. This capability allows the position of the crane 26 withrespect to the coiled tubing unit 12 to be varied. For example, if thetubing guide is rotated approximately 30 degrees, the crane 26 may bepositioned generally along side of the coiled tubing unit 12. Allowingmultiple positions of the ground equipment (coiled tubing unit and craneand/or telescoping mast) may be advantageous, especially at sites wherethere is a reduced clearance radius around the wellhead or there areother limitations on positioning of the equipment.

FIGS. 4A, 4B, 4C, and 4D illustrate a representative example of thebasic components of coupling 46. Although shown and described inreference to an arched support mounted to one end of a boom, mast orother elongated support structure, it can be adapted for other types ofcoiled tubing support structures, such as those shown or described inconnection with other figures. In this example, the coupling permits torotate up and down, to pivot or swing to either side of the boom, and toswivel so that the plane in which the coiled tubing support guide linescan be adjusted and placed at an angle to the axis of the boom. In thisexample, the coupling includes three joints, 47, 49 and 51, which arerepresented by pins, and parallel offset links 53, that allows thetubing support guide to pivot up and down about a generally horizontalaxis (a first axis), to swivel or rotate about a second axis that,generally speaking, is oriented vertically (depending on the positionfirst joint 47) and to swing from side to side about a third axis thatis generally parallel to the second axis.

FIGS. 5A and 5B illustrate another representative example coupling 55that is similar to coupling 46, but that does not swing from side toside. It omits joint 51 and offset links 53, with the arched supportguide being connected to joint 49. The coupling is therefore adjustablein only two degrees of freedom: it moves up and down about the pinforming joint 47, and swivels or pivots about the pin forming joint 49.Although omitted for clarity, couplings such as couplings 46 and 55would have additional elements for enabling the joints to be, in effect,locked in position or blocked from turning while tubing is being run.Furthermore, the positions of the joints could be controlled remotelyusing hydraulic cylinders or other types of positioning devices.

Although not illustrated, other examples of a coupling allows the tubingsupport guide only to be adjusted in one degree of freedom, or in morethan three degrees of freedom

Coupling a coiled tubing support guide, in the manner shown in FIGS.4A-D or 5A-B, to an elongated support structure such as boom 38 allowsthe reel of coiled tubing to be placed on either side, behind or infront of a crane, telescoping mast, or other type of elongated supportstructure. When the coiled tubing 34 is tensioned, the tensile load istransferred to the boom 38 of the crane 26 and is not imparted on thecoiled tubing injector 18, which is suspended over the well bore. Thus,the tension load can be accommodated independently of the coiled tubinginjector 18. Moreover, with the coiled tubing guide support, in thisexample arched support guide 36, generally aligned with the boom 38 ofthe crane, the forces imparted on the crane as a result of tensioningthe coiled tubing are primarily axial forces to the boom 38. Thus, thecrane 26 is more easily controlled without requiring the crane operatorto adjust or move the boom to counteract the load. If the arched supportguide 36 is positioned so that the loading force induced by the tensionin the coiled tubing is not aligned with the axis of the crane boom 38or other elongated support structure, the elongated support structuremay be subjected to bending moments, both upward and sideways. However,most cranes and other elongated support structures can handle some sideloads. Alternatively, the crane or other elongated support structure canbe positioned anywhere around the wellhead, provided that the crane iscapable of handling the lateral or side loads induced by the tension inthe coiled tubing.

FIGS. 6A and 6B are front and side views of an alternate embodiment ofan arrangement of equipment for running coiled tubing in a well bore.This embodiment shows an arched support guide 36 guide similar to thatshown in FIG. 3. However, in this embodiment, the arched support guide36 is fixed or mounted to one side of the boom 38 of the crane. Althoughthe offset configuration may produce a bending moment in the crane boom38, a majority of the load on the arched support guide will betransferred to the boom as an axial load. Similar to the in-lineembodiment shown in FIG. 3, the tension load is not transferred to thecoiled tubing injector 18 and the wellhead. The arched support guide maybe attached to the boom by a coupling that permits it to be, forexample, tilted forward and backward, and to swivel, similar to theembodiment shown in FIG. 3. However, due to the configuration of thetubing guide on the side of the boom crane, the ability of a coupling topermit swiveling could be limited by the boom 38.

FIG. 7 illustrates an alternate embodiment in which a rotatable wheel 50is used as a tubing support guide rather than an arched support guide36. The rotatable wheel 50 is fixed to the head 40 FIG. 7 of the boom 38of the crane and is disposed generally above the boom 38. It supportsthe coiled tubing 34 as it changes direction from the direction it comesoff from the storage reel to the downward direction where it can bereceived in the top of the coiled tubing injector 18. The radius of therotatable wheel creates a sufficient arch in the coiled tubing 34 toallow the change in direction. However, the radius is great enough thatthe coiled tubing does not kink or otherwise damage. As with the archedsupport guide of FIG. 3, the wheel 50 is attached to the boom by acoupling 46 for permitting its position or orientation to be adjusted.For example, a coupling similar to the one shown in FIGS. 4A, 4B, 5A and5B could provide a degree of adjustability of the position and alignmentof the wheel that allows some amount of freedom in terms being able toplace a storage reel for the coiled tubing to one side or the other ofthe crane by allowing the wheel to be at an angle to the central axis ofthe boom of the crane. However, alternately, the wheel may be mounted insuch a manner that the wheel has a fixed relationship to the centralaxis of the crane.

As shown in FIGS. 8A and 8B the rotatable wheel tubing guide 50 may,alternatively, be attached on one side of the crane boom 38 or otherelongated support structure, such as a telescoping mast.

Referring to FIG. 9, in another alternative embodiment, a coiled tubingguide structure can be placed on a telescoping mast, which is anotherexample of an elongated support structure. In this example, telescopingmast 60 supports the rotatable tubing support wheel 50, illustrated inFIGS. 8A and 8B. The rotatable wheel could also be mounted to mast 60 ina manner similar to which it is attached to crane boom 38 in FIG. 7.Similar to the crane boom 38, the telescoping mast 60 will be subjectedprimarily to tensile load induced by coiled tubing 34. Neither thecoiled tubing injector 18 nor the wellhead is subjected to anysignificant portion of the load. In certain embodiments, the telescopingmast may be mobile and mounted on a vehicle such as a trailer 62 asshown.

Reference is now made to FIG. 10. In this embodiment, the telescopingmast 60 supports an arched support guide 36 mounted to it at its headend using coupling 46, of the type shown in FIG. 7, for permitting it tobe adjusted. In this example, it can be adjusted as described inconnection with FIGS. 4A-D, or 5A and 5B. However, the coupling could,as in the embodiment of FIG. 3, permit adjustment in one or more degreesof freedom. In this embodiment, crane 26 is positioned opposite thetelescoping mast trailer 62 and the reel 10 (which is part of coiledtubing unit 12) and supports the coiled tubing injector 18. However, itcould be positioned anywhere around the wellhead. In this example, thetelescoping mast 60 is used only to support and position a coiled tubingsupport guide, such as arched support guide 36. In an alternativeembodiment, the injector 18 may be suspended by the mast 60 eliminatingthe need for the crane. It should be noted that other embodimentsdescribed and shown in this disclosure may employ a separate crane orother lifting and supporting device to support the coiled tubinginjector 18, while a coiled tubing support guide is attached to aseparate elongated support structure such as crane boom 38 ortelescoping mast 60, whether it is an arched support guide 36 orrotatable wheel 50, like the one shown in FIG. 7, or other type ofsupport guide suitable for coiled tubing.

FIG. 11 illustrates an example of relative positions of the coiledtubing unit 12 (and thus also reel 10) and the crane 26. In thisembodiment, the crane 26 is positioned in front of the coiled tubingunit 12 substantially aligned with an imaginary line between thewellhead and the coiled tubing unit 12. As such, the force exerted onthe crane boom 38 by the tension on the coiled tubing is in the sameplane as the axis of the crane boom 38.

However, in certain oil well servicing operations, ground clearanceconstraints may require that the reel 10 and the crane 26 be positionedsubstantially side-by-side. This configuration is shown in FIG. 12. Inthis configuration, a coupling such as coupling 46 may be employed toswivel the coiled tubing support guide (for example, arched supportguide 36 or rotatable wheel 50). With a coiled tubing unit 12 carryingreel 10 positioned to the side of the crane, the plane of coiled tubingsupport guide will need to swivel up with respect to the axis of thecrane boom 38. This adjustability of a coupling that permits the coiledtubing support guide to be swiveled allows the coiled tubing 34 from thestorage reel 10 disposed to be properly supported by the tubing guide.Thus, the coiled tubing guide structure can be fully supported by thecrane boom 38 without the crane boom 38 being aligned with the coiledtubing 34 extending upward from the storage reel 10.

Reference is now made to FIG. 13. The illustrated embodiment is similarto that shown in FIG. 7, with the coiled tubing unit 12 being positionedbetween the wellhead and the crane 26, generally along a line betweenthe crane and the wellhead. Although wheel 50 is used as a coiled tubingsupport guide, an arched support guide could be employed instead.Similarly, a telescoping mast may be employed instead of crane 26.

Reference is now made to FIG. 14. In this example, an arched supportguide 36 mounted to crane boom 38 is positioned to allow the coiledtubing unit 12 to be positioned generally opposite the wellhead from thecrane boom 38. The coupling 46, attaches arched support guide 36 to thehead 40 of the boom. Alternately, rotatable wheel 50 may be attached tothe boom 38, or a telescoping mast 60 may be employed in place of thecrane. In this example, the load induced by the tension in the coiledtubing 34 is predominately a downward bending moment on the boom 38,generally in the vertical plane of its axis if the reel 10, wellhead andcrane are generally in line with each other.

Referring now to FIGS. 15A-15C and 16A-C illustrate alternateembodiments of an apparatus and a method for relieving bending loads ona wellhead during conventional rigging of a coiled tubing injector on awell head. In these embodiments a bending-resistant coupling is formedbetween the end of the elongated support structure (for example, a craneboom, extendable mast, or similar structure) and a coiled tubinginjector unit. The bending-resistant coupling forms a rigid connectionfrom the head of the elongated support unit to the top of riser 22 onceit is coupling of its two members occurs. The rigid connection, at leastduring expected loads, prevents tension on coiled tubing 34 frominducing a bending moment on the wellhead or substantially limiting theamount of bending to an otherwise acceptable level. However, thebending-resistant coupling in these examples permits relative rotationof a coiled tubing injector 18 with respect to the elongated supportstructure. During pick up and maneuvering of the coiled tubing unittoward the wellhead with the elongated support structure, the freedom ofthe coiled tubing injector unit to rotate with respect to the elongatedsupport structure allows the coiled tubing injector 18, and inparticular tubing support guide 16 attached to it, to maintain the sameorientation with respect to reel 10.

In the two example embodiments, the bending-resistant coupling iscomprised of two coupling members. An upper coupling member is connectedto the elongated support structure, and a bottom coupling member isconnected with the coiled tubing unit. A hoist line extending down fromthe elongated support structure is connected to either the bottomcoupling member or the coiled tubing injector. The hoist line is used toraise the coiled tubing injector from the back of at trailer or otherlocation in which it is being rigged for placement on top of thewellhead. When ready to be connected to the wellhead, the lower couplingmember is raised into engagement with the upper coupling member. Thesurfaces along which the coupling members engage are, in the examples,circular in cross-section, to allow for rotation. In both embodiments,the central axis defined by the respective coupling members arecoincident with each other, as well as with an axis extending from thewell head 20, along the riser, to a sheave, pulley or wheel, winch, orother connection point on the head of the elongated support structure.

In the embodiment of FIGS. 15A-C cooperating or engaging surfaces of thecoupling members are cylindrical, with one member fitting inside theother. The lengths of the cylindrical portions of the members aresufficient for the portions of those surfaces that engage each otherwhen the two members are coupled to cooperate to resist substantialbending of the coupling. In the embodiment of FIGS. 16A-C bending isresisted by pulling the bottom coupling member up, using the hoist line,until complementary mating surfaces that are oblique to the central axisof each on each of the coupling members touch, and using tension on thehoist line to maintain that engagement.

During rigging, the top coupling is attached to the crane boom, mast orother elongated support member being used to move to and support overthe wellhead the coiled tubing injector. The bottom coupling isconnected to the coiled tubing injector when it is on the ground ortrailer. The hoist line is then connected to a lift point on the bottomcoupling or coiled tubing injector. At this point, the end of theelongate support member is typically much higher above the ground thanthe top of the coiled tubing injector. When the coiled tubing injectoris ready to be positioned over the wellhead, the hoist line is used tolift the coiled tubing injector up until the bottom coupling engages orcouples with the top coupling. The bottom and top coupling members willdisengage when the hoist line is lowered. In these example no device ormechanism, other than the hoist line, is required to connect the twocoupling members after they have been coupled. Alternately, such adevice or mechanism could be used.

Referring to the embodiment of FIGS. 15A-C, coupling assembly 52connects the coiled tubing injector 18 to the head 40 of the crane boom34. Crane boom 34 is intended to be representative of an elongatedsupport structure. The coupling assembly forms a rigid connection fromthe head 40 to the top of riser 22. The rigid connection avoids placinga bending moment on the wellhead that would otherwise result, if thecoiled tubing injector 18 were allowed simply to hang form the mainhoist line, from a pulling force generated by the reel 10 as it coilsthe tubing being wound on the drum of the reel and maintains tension onthe coiled tubing 34 necessary for keeping the tubing spooled properlyon the reel drum.

In this example a cylindrical member 56, made from, for example, a shortlength of pipe, comprises a top coupling member. The bottom couplingmember is comprised of hollow cylindrical member 58, which could also bemade from a length of pipe. It has inner cylindrical surface with innerdiameter larger than the outer diameter of cylindrical outer surface ofcylindrical member 56. When the coupling is pulled together along acentral axis common to both cylindrical members, so that they at leastpartially overlap, at least a portion of the inner surface of hollowcylindrical member 58 surrounds and engages at least a portion of theouter surface of cylindrical member 56. Such portions will be referredto herein as an engaging surface. The cylindrical members 56 and 58 canrotate with respect to one another and translate axially with respect toone another while, as long as they remain engaged, maintaining acoupling that resists a load caused by tension on the coiled tubing thatwould otherwise allow bending moments on the riser 22 and wellhead 20.Note, however, that some bending may occur due to spacing between thecylinders. Such spacing might exist to allow the cylindrical members tocouple and then move axially and rotationally with respect to eachother.

Cylindrical member 56 is attached to the head 40 of the crane by yoke60. In this example the yoke is attached to the ends of an extended loadshaft 47 of sheave 45. However, different structures can be used toattach the cylindrical member to the crane or to a mast or otherelongated support structure. Cylindrical member 58 is connected to, andsupported above, a top of the coiled tubing injector 18 through a frame62. Hoist hook 42 is connected to a hook or latch member 64 that isconnected to or otherwise part of the framework. The frame 62 providessufficient clearance to allow tubing support guide 16 to connect to thetop of the coiled tubing injector 18.

In this example, the frame 62 is connected to the top of the frame 18 athrough a balancing mechanism that allows the position of the coiledtubing injector 18 to be shifted from side to side with respect to thelift point at which hook 42 is attached, so that the center of gravityof the coiled tubing injector unit, is directly below the lift point,thereby compensating for the weight of the tubing support guide 16extending to one side. The balancing mechanism, in this example, allowsfor translational movement of the coiled tubing injector 18 with respectto the frame 62 by means of one or more tracks 66 mounted and aplurality of rollers 68. The tracks 66 are connected to frame 62 and therollers 68 are connected to the frame 18 a of the coiled tubing injector18. Once the coiled tubing injector unit is positioned correct, it ispinned, bolted, or otherwise fixed to the frame 62.

FIGS. 16A-C illustrate an alternate embodiment in which thebending-resistant coupling is comprised of a pair of concentric rings 70and 72. Although the rings, in this example, have engaging surfaces thatare cylindrically shaped, they are too short to provide resist bending.The rings include concentric cylindrical surfaces 70 a and 72 a, havinga common central axis that is generally aligned vertically when thecoiled tubing injector 18 is freely hanging from hook 42. The rings alsopresent mating surfaces 70 b and 72 b, respectively, that are orientedat an oblique angle with respect to the cylindrical surfaces 70 a and 72a. In this example, they generally lay within a plane that isperpendicular to the cylindrical surfaces 70 a and 72 a. When the tworings are pulled together to engage at least along the mating surfaces70 b and 72 b, and then held in that position, the coupling resistsbending. The concentric cylindrical surfaces 70 a and 72 a maintainalignment of the mating surfaces, at least while they are engaged, andtend to assist with alignment during the coupling process.Alternatively, rather than having two surfaces that engage, mate orotherwise cooperate, each ring could present to the other ring a singlecomplementary surface with which the other could engage to resistbending. This surface could, for example, be conical in shape, whichwould function to both guide and center the two rings, as well asprovide mating surfaces that resist a bending moment on the two parts ofthe coupling.

Rotation is possible at least before the two rings engage, as well asafter the rings engage, depending on the amount of friction. Translationmovement of the two rings with respect to each other is enabled byraising and lowering the hook 42.

Hook 42 is connected to a balancing harness 76, which in turn isconnected to the frame of straightener 19, which in turn is connected tothe frame 18 a of the coiled tubing injector unit. If no straightener isincluded, the balancing harness 76 would be connected directly to frame18 a of the coiled tubing injector 18. The balancing harness 76 allowsthe position of the coiled tubing injector 18 and straightener 19 to bemoved so that its center of gravity of aligns with the lift point (thepoint at which hook 42 connects to the balancing harness).

Frame 78 connects the lower ring 72 to the coiled tubing injector 18 or,in this example, which includes straightener 19, to the top of the frameof the straightener 19, which is in turn connected to the frame 18 a ofthe coiled tubing unit in a fixed relationship. Yoke 80 connects theupper ring 70 to the extended load shaft 47 of sheave 45.

The embodiment of FIG. 17 does not include a coupling and allows thecoiled tubing injector 18, to which is attached tubing support guide 16,to hang in a conventional manner from main hoist line 44. An extensionarm 82 mounted to the head 40, a pulley or sheave 84 mounted at one endof the arm, and a line run around the pulley or sheave. The line isconnected to tubing support guide 16 to apply a force that counteractsthe force from the tension on coiled tubing 34 that would induce abending moment on riser 22 and the wellhead 20.

Referring now to FIG. 18, in order to perform a service on an oil andgas well using the exemplary arrangements illustrated in FIGS. 3-17, anelongated support structure, such as crane 26, a telescoping mast, orother structure, is transported to the site and set up in position nearthe well head 20, and a coiled tubing support guide is mounted to theelongated support structure. Also transported to the site are a reel ofcoiled tubing 10, a coiled tubing injector 18, and one or more blowoutpreventers, risers and other equipment and tools needed for connectingthe coiled tubing injector to the wellhead, as well as power packs andcontrols for operating the reel and injector. Although there are manydifferent ways and to setup this equipment to perform a service on thewell, which depends in part on the type of the service to be performed,the process generally involves, in no particular order, connecting theblowout preventers and riser to the well, feeding coiled tubing fromreel into the injector, over the coiled tubing support guide, andhoisting the injector in place above the wellhead using either thecrane, telescoping mast or other type elongated support structure. Oncethe injector is connected to the wellhead and the free end of the coiledtubing is connected with a tool, the injector is then operated to runthe coiled tubing in and out of the well bore, and the storage reel ofcoiled tubing is operated in conjunction with the injector to maintainat least a predetermined tension of the coiled tubing as the coiledtubing is being spooled on to, and unspooled from, the reel.

FIG. 18 shows a preferred placement of the base of a crane 26 or thebase of other elongated support structure with respect to the reel 10 ofcoiled tubing unit 12 and wellhead 20. When the coiled tubing injector18 is initially hoisted off the back of the trailer 11 by, for example,crane 26, the position of its boom 38 is indicated by a line 88. As thecoiled tubing injector 18 is maneuvered by the crane and connected towell head 20, the orientation of the boom is indicated by line 88, whichis a line extending between the base of crane, where the boom attaches,and the well head. Line 90 extending between the coiled tubing reel 10and the wellhead 20 generally indicates the path of the coiled tubing34, and thus also the direction of the force generated by the tension onthe coiled tubing. The angle 92 formed between liens 88 and 90 is,preferably not greater than 70 degrees in a first embodiment, notgreater than 30 degrees in a second embodiment, and not greater thantwenty degrees in a third embodiment.

The foregoing description is of exemplary embodiments. Alterations andmodifications to the disclosed embodiments may be made without departingfrom the inventions taught by the examples. The meanings of the termsused in this specification are, unless expressly stated otherwise,intended to have ordinary and customary meaning, and are not intended tobe limited to the details of the illustrated structures or the disclosedembodiments.

What is claimed is:
 1. An apparatus for coupling a coiled tubinginjector from a boom or mast for positioning the coiled tubing injectorabove a wellhead, comprising a first structure, adapted for connectingto a coiled tubing injector unit, comprising a first coupling memberhaving an opening with a cylindrically shaped inside surface; a secondstructure adapted for connecting to an end of the elongate support, thesecond structure comprising a second coupling member havingcylindrically shaped outer diameter for positioning within, and closelyfitting against, the cylindrically shaped inside surface of the openingin the first coupling member, the second coupling member having anopening through which a line may pass for connection to the firststructure.
 2. The apparatus of claim 1, wherein the first and secondcoupling members are elongated and free to move with respect to eachother, without decoupling, a predetermined distance along an along anaxis that is coincident with a center axis of both the cylindricallyshaped inner surface of the opening in the first coupling member and thecylindrically shaped outer surface of the second coupling member.
 3. Theapparatus of any one of claim 1, wherein the second structure is adaptedfor connecting to a sheave axle on the boom or mast.
 4. An apparatus forcoupling a coiled tubing injector from an elongated support member forpositioning the coiled tubing injector above a wellhead, comprising afirst structure, adapted for connecting to a coiled tubing injectorunit, comprising a first coupling member having a ring shape and anopening through which a hoist line may pass; a second structure adaptedfor connecting to an end of the elongate support, the second structurecomprising a second coupling member having a ring shape and an openingthrough which the hoist line may pass for connection to the firststructure; wherein the first and second coupling members each comprise acomplementary mating surface for cooperating to allow relative rotationof the first and second coupling members around a central axis and toresist a bending at the coupling along the central axis.
 5. A coiledtubing injector assembly for suspending above a wellhead from a boom ormast comprising: a coiled tubing injector mounted within a frame; acoiled tubing guide connected with the frame; a bending-resistantcoupling structure connecting the frame with the telescoping boom ormast, the bending-resistant coupling structure adapted for allowingrelative rotation of the coiled tubing injector with respect to the boomor mast during rigging of the coiled tubing injector to the well head.6. The coiled tubing injector assembly of claim 5, wherein thebending-resistant coupling structure is adapted for permitting permitstranslation movement along an axis about which the coupling permitsrelative rotation of the coiled tubing injector with respect to the boomor mast during rigging.
 7. The coiled tubing injector assembly of claim5, wherein the bending-resistant coupling structure comprises: a firststructure, adapted for connecting to a coiled tubing injector unit,comprising a first coupling member having an opening with acylindrically shaped inside surface; a second structure adapted forconnecting to an end of the elongate support, the second structurecomprising a second coupling member having cylindrically shaped outerdiameter for positioning within, and closely fitting against, thecylindrically shaped inside surface of the opening in the first couplingmember, the second coupling member having an opening through which aline may pass for connection to the first structure.
 8. The coiledtubing injector assembly of claim 7, wherein the first and secondcoupling members are elongated and free to move with respect to eachother, without decoupling, along an axis that is coincident with acenter axis of both the cylindrically shaped inner surface of theopening in the first coupling member and the cylindrically shaped outersurface of the second coupling member.
 9. The coiled tubing injectorassembly of claim 5, wherein the bending-resistant coupling comprises: afirst structure, adapted for connecting to a coiled tubing injectorunit, comprising a first coupling member having a ring shape and anopening through which a hoist line may pass; a second structure adaptedfor connecting to an end of the elongate support, the second structurecomprising a second coupling member having a ring shape and an openingthrough which the hoist line may pass for connection to the firststructure; wherein the first and second coupling members each comprise acomplementary mating surface for cooperating to allow relative rotationof the first and second coupling members around a central axis and toresist a bending at the coupling along the central axis.
 10. The coiledtubing injector assembly of claim 5, wherein the bending-resistantcoupling is adapted for connecting to a sheave axle on the boom or mast.11. A method for injecting and withdrawing coiled tubing into and from awell bore, comprising: connecting a top half of a bending-resistantcoupling to an elongated support member for positioning a coiled tubinginjector over a wellhead; connecting a bottom half of abending-resistant coupling; positioning a reel of coiled tubing and acoiled tubing injector unit near a wellhead; and connecting a hoist linefrom the mast or boom to a lift point for lifting the bottom couplingand coiled tubing injector; lifting with hoist line the coiled tubinginjector up until the bottom coupling engages or couples with the topcoupling; and maneuvering the coiled tubing injector unit to a positionover the wellhead.
 12. The method of claim 11, wherein thebending-resistant coupling comprises: a first structure, adapted forconnecting to a coiled tubing injector unit, comprising a first couplingmember having an opening with a cylindrically shaped inside surface; asecond structure adapted for connecting to an end of the elongatesupport, the second structure comprising a second coupling member havingcylindrically shaped outer diameter for positioning within, and closelyfitting against, the cylindrically shaped inside surface of the openingin the first coupling member, the second coupling member having anopening through which a line may pass for connection to the firststructure.
 13. The method of claim 11, wherein the bending-resistantcoupling comprises: a first structure, adapted for connecting to acoiled tubing injector unit, comprising a first coupling member having aring shape and an opening through which a hoist line may pass; a secondstructure adapted for connecting to an end of the elongate support, thesecond structure comprising a second coupling member having a ring shapeand an opening through which the hoist line may pass for connection tothe first structure; wherein the first and second coupling members eachcomprise a complementary mating surface for cooperating to allowrelative rotation of the first and second coupling members around acentral axis and to resist a bending at the coupling along the centralaxis.
 14. A method for injecting and withdrawing coiled tubing into andfrom a well bore, comprising: positioning a reel of coiled tubing and acoiled tubing injector unit near a wellhead; and placing a base, aboutwhich an elongated support structure, can pivot near the wellhead andthe coiled tubing in injector; picking up the coiled tubing injectorunit with a free end of the elongated support structure, and maneuveringthe coiled tubing injector unit to a position over the wellhead forconnection to the wellhead; wherein an angle formed between a lineextending from the base of the elongated support structure and thewellhead, and a line between wellhead and the coiled tubing reel, is notgreater than seventy degrees.
 15. The method of claim 14, furthercomprising coupling the coiled tubing injector to the free end of theelongated support structure with a bending-resistant coupling.
 16. Themethod of claim 14, wherein coiled tubing extends between the reel andthe coiled tubing injector unit, over a support guide affixed to thecoiled tubing unit, during maneuvering of the injector unit, and whereinthe bending-resistant coupling between the coiled tubing injector unitand the elongated support structure permits for relative rotation of thecoiled tubing unit with respect to the elongated support structure,thereby allowing for the support guide to remain positioned between thereel and coiled tubing injector during maneuvering.
 17. An apparatus forsupporting coiled tubing being injected into and withdrawn from a wellbore, comprising a coiled tubing guide structure adapted for mounting toa head of an elongated support structure opposite the first end, forsupporting coiled tubing extending between a storage reel and a coiledtubing injector when positioned over a well head, whereby a load on thecoiled tubing guide induced by tension on the coiled tubing istransferred to the elongated support structure and not the wellhead viathe coiled tubing injector.
 18. The apparatus of claim 17, wherein thecoiled tubing is injected into the well bore by a coiled tubing injectorsupported by the elongated support structure.
 19. The apparatus of claim17, wherein the elongated support structure is comprised of a boom of acrane.
 20. The apparatus of claim 17, wherein the elongated supportstructure is comprised of a telescoping mast.
 21. The apparatus of claim17, wherein the coiled tubing guide structure is aligned in the samevertical plane as a central axis of the elongated support structure. 22.The apparatus of claim 17, wherein the coiled tubing guide structure isoffset to one side of the elongated support structure.
 23. The apparatusof claim 18, wherein the tubing guide is comprised of a rotatable wheel.24. The apparatus of claim 23, wherein the rotatable wheel is disposedin-line with the elongated support structure.
 25. The apparatus of claim24, wherein the rotatable wheel is offset to one side from the elongatedsupport structure.
 26. An apparatus comprising: a coiled tubing injectorconnected with a wellhead of a well; a reel from which coiled tubing isunwound and threaded into the coiled tubing injector, over a tubingguide support structure; and an elongated support structure forpositioning the tubing guide support structure over the coiled tubinginjector without affixing the coiled tubing support guide to the coiledtubing injector.
 27. The apparatus of claim 26, wherein the tubing guideis supported independently of a wellhead associated with the well bore.28. The apparatus of claim 26, wherein the coiled tubing support guideis coupled to the elongated support structure through a coupling forpermitting the orientation of the coiled tubing support guide to beadjusted relative to the elongated support structure.
 29. A method forinjecting and withdrawing coiled tubing into and from a wellhead,comprising: positioning a storage reel holding coiled tubing near awellhead; positioning a base connected to first end of an elongatedsupport structure nearing the wellhead and positioning a second, freeend, having mounted to it a coiled tubing support guide, above thewellhead; extending the coiled tubing from the storage reel andsupporting the coiled tubing using the tubing guide, the coiled tubingsupport guide forming an arch in the coiled tubing; and connecting to awellhead a coiled tubing injector, the coiled tubing from the storagereel extending over the coiled tubing support guide and into the coiledtubing injector, the elongated support structure holding the coiledtubing support guide above the coiled tubing injector without it beingconnected with the coiled tubing injector.
 30. The method of claim 29,wherein the coiled tubing injector is hanging from a line extending fromthe elongated support structure.
 31. The method of claim 19, wherein thebase is positioned between the storage reel and the wellhead.
 32. Themethod of claim 29, wherein the base is positioned on an opposite sideof the wellhead from the storage reel.
 33. The method of claim 29,wherein the base is positioned adjacent to one side of the storage reel.34. The method of claim 29, further comprising operating the coiledtubing injector to run the coiled tubing in and out of the wellhead,into a well bore, and operating the storage reel to maintain at least apredetermined tension on the coiled tubing extending between the storagereel and the coiled tubing injector.